Fix PIC build broken by d9145241fe378104ba4c12a42534549faacc92e6.

Under PIC configuration, FT_{CFF,PSCMAPS,SFNT,TT}_SERVICES_GET
take no arguments but derefer the variable named `library'
internally.

* src/cff/cffdrivr.c (cff_get_interface): Declare `library' and
set it if non-NULL driver is passed.
* src/truetype/ttdriver.c (tt_get_interface): Ditto.

* src/sfnt/sfdriver.c (sfnt_get_interface): Declare `library'
under PIC configuration, and set it if non-NULL module is given.
* src/psnames/psmodule.c (psnames_get_interface): Ditto.
5 files changed